An integrated circuit may include logic circuits containing n-channel metal oxide semiconductor (NMOS) transistors and p-channel metal oxide semiconductor (PMOS) transistors. Logic circuits are characterized by circuit elements such as NAND gates, NOR gates and/or binary adders. Some logic circuits are used as input/output circuits for digital signals transmitted into and out of the integrated circuit. Input/output circuits may operate at higher voltages than core logic circuits in the integrated circuit. The integrated circuit may further include analog circuits containing NMOS transistors in circuit elements such as oscillators. It may be desired to operate the analog circuit at high frequencies, which may require a gate length of the NMOS transistors in the analog circuit elements to have gate lengths comparable to gate lengths of the NMOS transistors in the logic circuits. It may also be desired to operate the analog circuit at a low noise level. It may further be desired to fabricate the integrated circuit within a target cost. Attaining these three goals may be problematic, in that high speed NMOS transistors formed using logic fabrication processes frequently exhibit undesirable noise levels.